In the past, as a process for producing dicyanonorbornane (hereinafter referred to as DCN) by causing hydrogen cyanide to reaction with cyanonorbornene (hereinafter referred to as CNN), for example, the following methods are known:
1) a method involving using a cobalt carbonyl catalyst and triphenyl phosphine as a catalyst system (refer to Patent Document 1); and
2) a method involving using a zerovalent nickel complex catalyst and a Lewis acid as a catalyst system (refer to Patent Documents 2 and 3).
However, in the above methods 1) and 2), since the yield was low, an expensive catalyst was used and the methods were for isolating a complex involving a purification step, there have been problems in the decreased yield and the troublesome workability.
Then, there has been proposed a new method regarding the synthesis of a zerovalent nickel complex catalyst or the like, enabling to overcome conventional problems in such techniques (refer to Patent Document 4). According to the method as described in Patent Document 4, the synthesis of the zerovalent nickel complex catalyst was extremely easy and the yield became high.
However, it has been known that 2,5(6)-bis aminomethyl-bicyclo[2,2,1]heptane (hereinafter referred to as NBDA) obtained by the catalytic hydrogenation of DCN obtained by using the method as described in Patent Document 4 as a raw material has a property that time-dependent coloring is extremely great. It has been known that phenol remained in a raw material DCN is also mixed in NBDA as an impurity, whereby time-dependent coloring occurs. That is, this coloring is mainly caused by phenol contained in NBDA. Accordingly, in order to reduce coloring, there has been proposed a method involving prescribing the amount of phenol in NBDA for reducing the amount of phenol in the purification step (refer to Patent Document 5).
Patent Document 1: U.S. Pat. No. 2,666,780
Patent Document 2: Japanese Patent Laid-open No. 1991-95151
Patent Document 3: U.S. Pat. No. 3,328,443
Patent Document 4: Japanese Patent Laid-open No. 2003-55328
Patent Document 5: Japanese Patent Laid-open No. 2002-69043